2

我有几个线程使用类似于下面的代码的东西从队列中消费任务。问题是有一种类型的任务在处理任何其他任务时无法运行。

这是我所拥有的：

while (true) // Threaded code
{
    while (true)
    {
        lock(locker)
        {
            if (close_thread)
                return;

            task = GetNextTask(); // Get the next task from the queue
        }

        if (task != null)
            break;

        wh.WaitOne(); // Wait until a task is added to the queue
    }

    task.Run();
}

这就是我需要的：

while (true)
{
    while (true)
    {
        lock(locker)
        {
            if (close_thread)
                return;

            if (disable_new_tasks)
            { 
                task = null; 
            }
            else
            {
                task = GetNextTask();
            }
        }

        if (task != null)
            break;

        wh.WaitOne();
    }

    if(!task.IsThreadSafe())
    {
        // I would set this to false inside task.Run() at 
        // the end of the non-thread safe task
        disable_new_tasks = true;  
        Wait_for_all_threads_to_finish_their_current_tasks(); 
    }

    task.Run();
}

问题是我不知道如何在不造成混乱的情况下实现这一目标。

4

4 回答 4

1

Try looking to using a TreadPool and then using the WaitHandle.WaitAll method to determine that all threads have finished executing.

MSDN

于 2010-12-24T07:52:57.487 回答
0

WaitHandle.WaitAll(autoEvents); 也许这就是你想要的。

class Calculate
    {
        double baseNumber, firstTerm, secondTerm, thirdTerm;
        AutoResetEvent[] autoEvents;
        ManualResetEvent manualEvent;

        // Generate random numbers to simulate the actual calculations.
        Random randomGenerator;

        public Calculate()
        {
            autoEvents = new AutoResetEvent[]
            {
                new AutoResetEvent(false),
                new AutoResetEvent(false),
                new AutoResetEvent(false)
            };

            manualEvent = new ManualResetEvent(false);
        }

        void CalculateBase(object stateInfo)
        {
            baseNumber = randomGenerator.NextDouble();

            // Signal that baseNumber is ready.
            manualEvent.Set();
        }

        // The following CalculateX methods all perform the same
        // series of steps as commented in CalculateFirstTerm.

        void CalculateFirstTerm(object stateInfo)
        {
            // Perform a precalculation.
            double preCalc = randomGenerator.NextDouble();

            // Wait for baseNumber to be calculated.
            manualEvent.WaitOne();

            // Calculate the first term from preCalc and baseNumber.
            firstTerm = preCalc * baseNumber * 
                randomGenerator.NextDouble();

            // Signal that the calculation is finished.
            autoEvents[0].Set();
        }

        void CalculateSecondTerm(object stateInfo)
        {
            double preCalc = randomGenerator.NextDouble();
            manualEvent.WaitOne();
            secondTerm = preCalc * baseNumber * 
                randomGenerator.NextDouble();
            autoEvents[1].Set();
        }

        void CalculateThirdTerm(object stateInfo)
        {
            double preCalc = randomGenerator.NextDouble();
            manualEvent.WaitOne();
            thirdTerm = preCalc * baseNumber * 
                randomGenerator.NextDouble();
            autoEvents[2].Set();
        }

        public double Result(int seed)
        {
            randomGenerator = new Random(seed);

            // Simultaneously calculate the terms.
            ThreadPool.QueueUserWorkItem(
                new WaitCallback(CalculateBase));
            ThreadPool.QueueUserWorkItem(
                new WaitCallback(CalculateFirstTerm));
            ThreadPool.QueueUserWorkItem(
                new WaitCallback(CalculateSecondTerm));
            ThreadPool.QueueUserWorkItem(
                new WaitCallback(CalculateThirdTerm));

            // Wait for all of the terms to be calculated.
            **WaitHandle.WaitAll(autoEvents);**

            // Reset the wait handle for the next calculation.
            manualEvent.Reset();

            return firstTerm + secondTerm + thirdTerm;
        }
    }
于 2010-12-24T08:11:55.393 回答
0

您可以将其视为类似于允许任意数量的读取器或一个写入器的数据结构。也就是说，任意数量的线程都可以读取数据结构，但是写入数据结构的线程需要独占访问。

在您的情况下，您可以运行任意数量的“常规”线程，或者您可以拥有一个需要独占访问的线程。

.NET 具有可用于实现这种共享的ReaderWriterLock和类。ReaderWriterLockSlim不幸的是，这些课程都没有在 xbox 上可用。

Monitor但是，可以通过和ManualResetEvent对象的组合来实现读取器/写入器锁。我没有 C# 示例（为什么我会，因为我可以访问本机对象？），但是有一个简单的 Win32 实现，应该不难移植。

于 2010-12-24T08:49:21.403 回答
-1

你可以使用这样的东西，

ExecutorService workers = Executors.newFixedThreadPool(10); 

   for(int i=0; i<input.length; i++) {
       Teste task = new Teste(rowArray,max);//your thread class
       workers.execute(task);
   }

   workers.shutdown();//ask for shut down
   while(!workers.isTerminated()) {//wait until all finishes.

  try {
      Thread.sleep(100);//
      } catch (InterruptedException exception) {
      }   
      System.out.println("waiting for submitted task to finish operation");
    }

希望这有帮助。

于 2010-12-24T08:09:48.543 回答